虾青素和/或有氧运动对D-半乳糖诱导大鼠心脏衰老的干预作用

Effects of astaxanthin and/or aerobic exercise on D-galactose-induced myocardial aging in rats

目的探究虾青素和/或有氧运动延缓D-半乳糖诱导大鼠心脏衰老的潜在作用机制。方法SPF级3月龄SD雄性大鼠40只随机分为安静对照组(C组)、急性衰老模型组(D组)、急性衰老+虾青素组(DA组)、急性衰老+有氧运动组(DE组)及急性衰老+虾青素+有氧运动组(DAE组),每组各8只。C组不进行任何干预,急性衰老各组大鼠腹腔注射100 mg/kg·d的D-半乳糖,同时分别以20 mg/kg·d虾青素和/或运动强度为60%最大摄氧量的有氧运动进行干预,实验周期为6周。末次训练12 h后取心脏,光学显微镜观察心脏组织形态并检测相关生化指标。结果心脏组织形态,C组正常;与C组比较,D组出现心肌细胞排列紊乱、心肌纤维断裂及炎性细胞浸润等现象;DA、DE、DAE心肌细胞排列整齐、心肌纤维断裂及炎性细胞浸润情况有所缓解,DAE组最为显著,心肌组织形态更接近于正常状态。与C组比较,D组心脏组织超氧化物歧化酶(SOD)、γ-谷氨酸半胱氨酸合酶(γ-GCS)活性及沉默信息调节因子1(SIRT1)、核因子E2相关因子2(Nrf2)、血红素氧合酶(HO-1)、B淋巴细胞瘤因子-2(Bcl-2)蛋白质表达水平、Bcl-2/Bcl-2相关X蛋白(Bax)比值显著降低(P<0.05或P<0.01);细胞凋亡水平、Bax蛋白质表达、丙二醛(MDA)含量显著升高(P<0.05或P<0.01)。与D组比较,DA组心肌组织SIRT1、Nrf2、HO-1蛋白质表达均显著升高(P<0.05),Bax蛋白质表达及MDA含量显著降低(P<0.05或P<0.01);DE组心肌组织SOD活性和SIRT1、HO-1蛋白质表达显著升高(P<0.05或P<0.01),Bax蛋白质表达及MDA含量显著降低(P<0.05或P<0.01);DAE组心肌组织SOD、γ-GCS活性及SIRT1、Nrf2、HO-1、Bcl-2蛋白质表达和Bcl-2/Bax比值显著升高(P<0.05或P<0.01),细胞凋亡水平、Bax蛋白质表达及MDA含量极显著降低(P<0.01)。与DA、DE组比较,DAE组心肌组织SIRT1、Bcl-2蛋白质表达及Bcl-2/Bax比值均显著升高(P<0.05或P<0.01),细胞凋亡水平显著降低(P<0.05);心肌组织细胞凋亡水平、SIRT1和Bcl-2蛋白质表达水平及Bcl-2/Bax比值具有协同效应。结论虾青素和/或有氧运动干预均可通过上调SIRT1/Nrf2信号通路相关蛋白质表达,缓解和改善D-半乳糖诱导的氧化应激,降低心肌细胞凋亡水平,延缓大鼠心脏衰老。

Objective To investigate the potential mechanism of astaxanthin and/or aerobic exercise in relieving Dgalactose-induced myocardial aging in rats.Methods Forty SD male rats aged 3 months were randomly divided into five groups,with 8 rats in each group:control group(group C),aging model group(group D),aging + astaxanthin group(group DA),aging + aerobic exercise group(group DE) and aging + astaxanthin + aerobic exercise group(group DAE).There was no intervention for group C.The other four groups were intraperitoneally injected with 100 mg/kg·d D-galactose.Group DA,DE and DAE were treated with 20 mg/kg·d astaxanthin and/or aerobic exercise at 60% VO2 max,respectively.The experiment lasted for 6 weeks.Twelve hours after the last training,the rats were sacrificed for heart harvesting.The morphology of the heart tissue was observed under light microscope and the related biochemical indicators were measured.Results The morphology of myocardium in group C was normal.Compared with group C,the myocardial cell in group D showed disorder,fiber rupture and inflammatory cell infiltration.Compared with group D,groups DA,DE and DAE showed improvement,including orderly arrangement of myocardial cells,relieved myocardial fiber rupture and reduction of inflammatory cells,especially in group DAE.and the morphology of myocardial tissue in group DAE was much closer to normal.Compared with group C,the activity of superoxide dismutase(SOD),γ-glutamate cysteine synthase(γ-GCs) and the expression of sirtuin 1(SIRT1),nuclear factor erythroid 2-related factor 2(Nrf2),heme oxygenase-1(HO-1) and Bcell lymphoma-2(Bcl-2) in myocardium and the ratio of Bcl-2/Bcl-2-associated X(Bax) of group D decreased significantly(P<0.05 or P<0.01);the apoptosis level,the expression of Bax and the malondialdehyde(MDA) content increased(P<0.05 or P<0.01).Compared with group D,the expressions of SIRT1,Nrf2 and HO-1 in group DA increased significantly(P<0.05),while the expression of Bax and the MDA content decreased significantly(P<0.05 or P<0.01).The activity of SOD and the expressions of SIRT1,HO-1 in group DE increased significantly(P<0.05 or P<0.01),while the expression of Bax and the MDA content decreased significantly(P<0.05 or P<0.01).The activity of SOD,γ-GCs,the expressions of SIRT1,Nrf2,HO-1,Bcl-2 and the ratio of Bcl-2/Bax in group DAE increased significantly(P<0.05 or P<0.01);the apoptosis level,the expression of Bax and the MDA content decreased significantly(P<0.01).Compared with group DA and DE,the expression of SIRT1,Bcl-2 and the ratio of Bcl-2/Bax in group DAE were increased significantly(P<0.05 or P<0.01),and the apoptosis level decreased significantly(P<0.05).Astaxanthin and aerobic exercise had synergistic effect on the apoptosis level,the expression of SIRT1,Bcl-2 and the ratio of Bcl-2/Bax in myocardium.Conclusion Astaxanthin and/or aerobic exercise intervention can alleviate and improve D-galactose-induced oxidative stress,which is achieved by increasing the expression of proteins related to the SIRT1/Nrf2 signaling pathway.It can also reduce the level of cardiomyocyte apoptosis and delay the myocardial aging of rats.